JPS62286868A - Antiskid device - Google Patents

Abstract

PURPOSE:To prevent a vehicle brake from generating a skid phenomenon, by reducing a pressure of brake fluid in accordance with its pressure through a flow control valve when a wheel approaches to a locked condition. CONSTITUTION:Since a pressure of brake fluid in a locked condition high increases when a road surface is placed in a condition of high friction coefficient, the high pressure acts in a cylinder chamber 13 of a fluid pressure regulating part, and a flow control valve 31, whose valve unit 33 receives said fluid pressure being lowered against a spring 37, places seat parts 40A, 40B in a closed condition. In this way, the brake fluid, which passes through an orifice 42 of the valve unit 33 being inducted into a valve chamber 34, is returned to a reservoir through the valve chamber 34, through hole 35 and a discharge path 15. Since the pressure of the brake fluid in the time of locking low decreases when the road surface provides a low coefficient of friction, the pressure in the cylinder chamber 13 low decreases, and the valve unit 33 is placed in a condition it is adapted to a retainer 38. In this way, the brake fluid is returned to the reservoir from the orifice 42 and the seat parts 40A, 40B of the valve unit 33 through the valve chamber 34.

Description

Detailed Description of the Invention 3. Detailed Description of the Invention "Field of Industrial Application" The present invention relates to a skid prevention device for vehicle brakes, and in particular, the skid prevention device of brake fluid is The present invention relates to a skid prevention device that reduces the pressure according to the pressure.

"Prior Art and Problems" A skid prevention device is provided in the middle of a path that transmits the pressure of brake fluid in a master cylinder operated by a brake pedal to the wheel cylinder of each wheel.
When the wheels approach a locked state during sudden braking, the brake fluid is continuously depressurized and pressurized to prevent wheels from skidding, ensure directional stability, and shorten braking distance.

FIGS. 4 to 6 show a conventional example of such a skid prevention device, and the skid prevention device includes a lock detection section A that detects the locked state of the wheels, and The hydraulic pressure modulating section B lowers the pressure of the brake fluid accordingly, and the pump section C increases the reduced brake pressure again.

In normal operating conditions, as shown in FIG. 5, the ball valve body 2 in the valve chamber I of the hydraulic pressure modulating section B is pushed up by the piston 3 and is connected to the master cylinder. The flow path between the boat 4 and the boat 5 connected to the wheel cylinder is in communication state,
When brake fluid is supplied from the master cylinder to the boat 4 by operating the brake pedal, the brake fluid is sent to the boat 5 through the introduction chamber 6 of the pump section C, the communication passage 7, and the valve chamber 1, and is then delivered to the wheel cylinder. supply.

Furthermore, when the wheels approach a locked state at the time of sudden braking (7), the flywheel lO, which is supported in a connected state via a ball ramp mechanism 9 to a rotating shaft 8 that rotates in conjunction with the axle in the lock detecting section A, , and the rotating shaft 8, the lever is moved to the left in FIG. 6, and the lever 11 is depressed to operate the dump valve 12. This dump valve 12 is provided in the middle of the discharge passage 15 between the cylinder chamber 13 of the hydraulic pressure modulation part B and the return boat 14 connected to the reservoir of the master cylinder. is in a closed state, but by operating the lever U, it is opened and the brake fluid in the cylinder chamber 13 is led out to the reservoir. When the hydraulic pressure in the cylinder chamber 13 decreases due to this decrease in brake fluid, the piston 3 is lowered, and the ball valve body 2, which had been pushed up by the piston 3, is closed, and the wheel cylinder is closed. Brake fluid pressure transmission is cut off. Furthermore, the pressure within the pump chamber 17 of the pump section C that communicates with the cylinder chamber 13 via the communication passage 16 also decreases as the pressure within the cylinder chamber 13 decreases, causing the piston 18 within the pump chamber 17 to is lowered and brought into contact with an eccentric cam 19 integral with the rotating shaft 8. Then, by reciprocating the piston 18 by the cam 19, a pumping action occurs, and the brake fluid in the reservoir passes through the pump chamber 17 to the cylinder chamber 13 of the hydraulic pressure modulating section B.
In this case, since the dump valve 12 is in the open state, the pressure inside the cylinder chamber 13 does not increase.

On the other hand, as the flywheel IO is decelerated by the friction clutch 20 and the rotation of the wheel is restored, the rotational difference between the rotary shaft 8 and the flywheel 1G becomes smaller, and both are rotated by the ball ramp mechanism 9. They are integrated and return to an interlocking state. As a result of this return, the dump valve 12 becomes closed, the pressure inside the cylinder chamber 13 pressurized by the pump section C increases, and the piston 3
By the way, the ball valve body 2 is pushed up and transferred to the wheel cylinder.In this skid prevention device, a flow control valve 21 is provided between the cylinder chamber 13 of the hydraulic pressure modulation section B and the dump valve 12. The flow rate of the brake fluid returned to the reservoir via the path I5 is controlled in accordance with the pressure within the cylinder chamber +3 of the hydraulic pressure modulation section B.

As shown in an enlarged view in FIG. 4, this flow rate control valve 21 includes:
A valve body 22 is provided below the cylinder chamber [3 of the hydraulic pressure modulating section B to form an inlet of the discharge passage 15, and a retainer 23 having a plurality of holes 23a is provided at the upper opening of the valve body 22. A piston 25 is provided inside the valve body 22 and is biased toward the cylinder chamber 13 by a spring 24, and the tip of the piston 25 and the retainer 2 are arranged inside the valve body 22.
A ball valve body 27, which is biased by a spring 26 in the opposite direction to the piston 25, is housed between the piston 25 and the piston 25 so as to be vertically movable. In addition, an orifice 2 is provided on the upper side wall of the valve body 22.
8 is provided with relatively large-diameter communication holes 29 in the lower side wall, and a seat portion 30 with the ball valve body 27 is provided between these holes.
The orifice 28 is formed in an outer diameter with a slight distance between it and the orifice 28, and the orifice 28 is kept open at all times. The hole 29 is closed.

When the wheels approach a locked state when the coefficient of friction of the road surface is high, the pressure of the brake fluid in the cylinder chamber 13 becomes high, and the ball valve body 27 is lowered by that fluid pressure and is seated. 30 is closed, and the brake fluid flows out relatively slowly only through the orifice 28. On the other hand, when the coefficient of friction of the road surface is low, such as on the surface of water, a locking state may occur when the pressure of the brake fluid is relatively low. By doing so, the ball valve body 27 is connected to the piston 2.
5, the cylinder chamber 13 is pushed up.
The brake fluid therein is rapidly flowed out through both the orifice 28 and the communication hole 29.

However, in such a flow control valve 21, the ball valve body 27 and the piston 25 are separate bodies and move while the two members are in contact with each other, so that no action is exerted on the ball valve body 27. This force may not act directly on the piston 25, which may cause the responsiveness of the ball valve body 27 to deteriorate. In addition, the valve body 22 includes a piston 25,
Ball valve body 27 and two springs 24 that bias them
・Since the 26 are housed in a complicated combination, the manufacturing efficiency is poor, and in the case of Fig. 4, the orifice 2B needs to be provided in an inclined state, making processing difficult. There are other problems.

The present invention effectively solves the above-mentioned problems, and aims to improve the control function by increasing the responsiveness of the flow control valve, as well as to facilitate its manufacture and reduce costs. be.

"Means for Solving the Problems" In order to achieve the above object, the present invention has a flow control valve configured as follows. That is, a valve body, a valve body that is inserted into the valve body so as to be reciprocally movable in a flow path and closes the seat portion of the valve body by the hydraulic pressure from the chamber of the hydraulic pressure modulation unit, and the valve body. The valve body is composed of a spring that biases the body in a direction against the hydraulic pressure to open the seat portion when the hydraulic pressure is low, and a retainer that prevents the valve body biased by the spring from coming off from the valve body. , characterized in that the piston is provided with an orifice that communicates with the discharge passage.

"Function" In the skid prevention device of the present invention, when the brake fluid in the cylinder chamber of the hydraulic pressure modulation section is discharged, when the friction coefficient of the road surface is high when the wheels are locked, the high hydraulic pressure from the cylinder chamber causes the flow rate to increase. By closing the seat part of the control valve, the brake fluid flows out only through the orifice of the valve body.On the other hand, when the coefficient of friction on the road surface is low, the fluid pressure from the cylinder chamber is low, which reduces the flow rate. Assuming that the valve body of the control valve opens the seat part due to the biasing force of the spring,
To cause brake fluid to flow out in a large amount from both an orifice and between a seat part.

Embodiment An embodiment of the skid prevention device of the present invention will be described below with reference to FIGS. 1 to 3. In the figure, parts common to the conventional example are given the same reference numerals, and explanations thereof will be omitted.

This skid prevention device has a lock detection section, a hydraulic pressure modulation section, a pump section, etc., like the conventional example, but
In the discharge passage 15 between the cylinder chamber 13 of the hydraulic pressure modulation section and the reservoir of the master cylinder, a flow control valve 31 provided to control the outflow amount of brake fluid at the stage before the dump valve has a special structure. It is ingenious in that it has this feature.

This flow rate control valve 31 has a valve body 32 connected below the cylinder chamber 13 of the hydraulic pressure modulating section so as to form a bottom wall thereof, and has a piston-like shape that is movable up and down within the valve body 32. A valve body 33 is inserted. The valve body 3
3, its lower part is slidably inserted into the valve body 32 in close contact with the valve body 32, and its upper part is formed to have an outer diameter that is spaced from the inner circumferential surface of the valve body 32, and the valve chamber 34 is inserted therebetween. is forming. The valve chamber 34 is communicated with the discharge passage 15 through a through hole 35 provided at the side of the valve body 32, and an inlet port formed in an enlarged diameter state at the upper end of the valve body 32. 36, which communicates with the cylinder chamber [3.

Further, a spring 37 is provided between the valve body 33 and the pulp body 32 along the vertical direction, and the spring 37 biases the valve body 33 upward, that is, toward the cylinder chamber 13 side. On the other hand, a retainer 38 is provided at the upper end of the valve body 33 so as to cover the introduction 036,
The upper limit position of the valve body 33 is regulated.

The retainer 38 is formed in a plate shape that crosses the introduction port 36, and is provided with a large number of mesh-like holes 38g as shown in FIG. and are in communication with each other.

A conical large diameter part 39 having a slight distance from the inner circumferential surface of the inlet port 36 is integrally provided at the upper end of the valve body 33, and the conical surface of the large diameter part 39 and Valve body 32
A seat portion 40A that opens and closes the valve chamber 34 is located between the step portion and the stepped portion of the valve chamber 34.
40B is formed in the central part of the valve body 33, and a through hole 41 that opens into the valve chamber 34 is provided along the radial direction. Orifices 42 are arranged in series.

In other words, the cylinder chamber 13 and the valve chamber 34 are connected to each other by two flow paths: a flow path passing between both seat portions 40^ and 40B, and a flow path passing through the orifice 42 and the through hole 41.
It is designed so that the two can communicate with each other.

In the skid prevention device having the flow control valve 31 configured as described above, when the dump valve is opened when the wheels are locked and the brake fluid in the cylinder chamber 13 is returned to the reservoir of the master cylinder, the hydraulic pressure in the cylinder chamber 13 is Accordingly, the amount of brake fluid flowing out is controlled as follows.

That is, when the friction coefficient of the road surface is high, such as on a concrete surface, the pressure of the brake fluid is high when the lock state is reached, so that the cylinder chamber 13 of the hydraulic pressure modulation section
A high pressure is applied inside, and the valve body 33 of the flow control valve 31 receives this hydraulic pressure and is lowered against the spring 37, closing the seat portions 40^ and 40B as shown in FIG. shall be. Therefore, the brake fluid in the cylinder chamber 13 is
As shown by the arrow in FIG. 3, the orifice 42 of the valve body 33
The liquid is introduced into the valve chamber 34 through the valve chamber 34, and from the valve chamber 34 through the through hole 35 into the discharge passage 15 and returned to the reservoir. On the other hand, when the friction coefficient of the road surface is low, such as on a water surface, the pressure of the brake fluid at the time of locking is relatively low, so the pressure in the cylinder chamber 13 is low, and the flow rate control valve 31 is As shown in FIG. 1, the valve body 33 is brought into contact with the retainer 38 by the biasing force of the spring 37, that is, the seat portions 40A and 40B are opened. Therefore, part of the brake fluid in the cylinder chamber 13 passes through the orifice 42 of the valve body 33 as shown by the arrow in FIG.
40B, a large amount is guided into the valve chamber 34 and returned to the reservoir.

In this way, when the coefficient of Marin is high, the brake fluid is
The brake fluid is flowed out in relatively small amounts only through the orifice 42 of No. 3 to slow down the pressure reduction speed, and when the coefficient of friction is low, the brake fluid is flowed out in large quantities from both the seat portions 40A and 40B and the orifice 42, The speed of pressure reduction can be increased, and control can be performed in accordance with the friction coefficient of the road surface. In this case, since only the valve body 33 can be moved up and down, its responsiveness is less affected by other parts, and smooth movement is ensured. Since the body 33 is lightened by the orifice 42, its responsiveness is increased and reliable control can be performed. Further, since one of the two flow paths for controlling the flow rate is formed between the valve body 33 and the seat portions 40A and 40B of the pulp body 32, a slight movement of the valve body 33 causes the seat portion 40 to
^・It should be possible to open the 4QB reliably and widely, allowing for rapid depressurization.

On the other hand, the retainer 38 has a large number of mesh-like holes 38.
a), its fluid resistance is reduced and the influence on brake fluid outflow can be reduced.
In addition, even if foreign matter should enter the cylinder chamber 13, this prevents the foreign matter from entering and prevents obstructions such as clogging of the orifice 42, and also ensures that most of the many holes 38a are open. It is possible to ensure reliable outflow of brake fluid.

Although the seat portion 40A of the valve body 33 is formed by the conical surface of the large diameter portion 39 in one embodiment, it may be formed by a spherical surface or the like, and the detailed shape of the valve body 32, etc. may also be changed from one embodiment to the other. It is not limited.

"Effects of the Invention" As is clear from the above description, the skid prevention device of the present invention can provide the following effects.

(i) Since the only movable part of the flow control valve is the valve body, its movement can be made smooth, and since the valve body is provided with an orifice, the weight can be reduced and responsiveness can be improved;
In addition, since one of the two flow paths is formed between the seat part, the seat part can be reliably and widely opened with a slight movement of the valve body, and rapid pressure reduction can be performed. , it is possible to improve the original control function of the valve.

(ii) It can be constructed with a small number of parts such as a valve body, a valve body, and a spring, making it easier to manufacture and lower costs than conventional examples.

(iii) By forming the retainer into a plate shape and arranging a large number of holes in a mesh shape, the fluid resistance thereof is reduced and the influence on the outflow of brake fluid is reduced, and
It is possible to prevent the occurrence of failure by preventing foreign matter from entering.

[Brief explanation of the drawing]

1 to 3 show an embodiment of the skid prevention device of the present invention, in which FIG. 1 is a longitudinal cross-sectional view of a flow control valve, and FIG. 2 is an arrow taken along the line ■-■ in FIG. 3 is a vertical cross-sectional view of the flow control valve showing a state in which the seat portion is closed, and FIGS. 4 to 6 show a conventional example of a skid prevention device. 5 is a longitudinal sectional view of the whole, and FIG. 6 is a sectional view taken along the line V[-Vl in FIG. 5. 31...Flow control valve, 32...Valve body, 33...Valve body, 34...Valve chamber,
35...Through hole, 36...Inlet, 3
7... Spring, 38... Retainer, 38
a... Hole, 39... Large diameter part, 40A.
40B... Seat portion, 41... Through hole, 42... Orifice.

Claims (2)

[Claims] (1) A discharge passage for discharging the brake fluid in the chamber is connected to the hydraulic pressure modulation unit that controls the hydraulic pressure in the wheel cylinder between the master cylinder and the wheel cylinder, and the discharge passage is connected to the hydraulic pressure modulation unit that controls the hydraulic pressure in the wheel cylinder. A dump valve that is opened and closed by a lock detection section that detects the state, and a flow control valve that controls the outflow amount of brake fluid according to the hydraulic pressure in the chamber of the hydraulic pressure modulation section between the dump valve and the hydraulic pressure modulation section. In the skid prevention device, the flow control valve includes a valve body forming a part of the discharge passage; A valve body that closes a seat portion of the valve body by hydraulic pressure from a chamber of the hydraulic pressure modulating unit; and a valve body that is biased in a direction against the hydraulic pressure to open the seat portion when the hydraulic pressure is low. 1. A skid prevention device comprising a spring and a retainer that prevents a valve body biased by the spring from coming off from a valve body, and wherein the piston is provided with an orifice that communicates with a discharge path. (2) The retainer is formed in a plate shape that crosses the flow path in the valve body, and has a large number of holes arranged in a mesh shape. Anti-skid device.